Electric switch wafer assembly



L. H. L. MALAVIEILLE 3,472,985

ELECTRIC SWITCH WAFER ASSEMBLY Oct. 14, 1969 2 Shets-Slieet Filed Aug. 10, 1967 LOWS /mnr Zucmv NALAWFILLF 77/ g wzfiu 19779 RMf/J 14, 6 1.. H. L. MALAVIEILLE 3,472,985

ELECTRIC SWITCH WAFER ASSEMBLY Filed Aug. 10, 1967 2 Sheets Sheet 2 lNvn/TUR I LOUIS lew" LUCIIGN MAM WEN-L5 "ram/Ev:

United States Patent 3,472,985 ELECTRIC SWITCH WAFER ASSEMBLY Louis Henry Lucien Malavieille, 39 Blvd. Suchet, Paris, France Filed Aug. 10, 1967, Ser. No. 659,727 "Claims priority, application 1France, Nov. 16, 1966,

Int. Cl. K011i 19/58, 21/78 US. Cl. 200166 5 Claims ABSTRACT OF THE DISCLOSURE SUMMARY OF THE INVENTION The invention has for an object an electric switch wafer.

It is known that in electrical or electronic technology, a switch device is currently used which comprises: a cylindrical shaft having lateral flats, mostly called an axle and which traverses a bearing rigidly fixed to a circular metallic plate carrying on opposite sides two fixed stems, parallel to the shaft at a standard distance from each other. Upon these stems or pillars are threaded substantially flat generally circular parts, of insulating material, separated by tubular spaces upon the said pillars. This device is assembled by clamping nuts, screwed upon the threaded ends of the two pillars.

These insulating parts or plates, which play a role or stator, are pierced by a central opening concentric with the shaft. They support all around their circumferences electrical contacts shaped as clips, of which the contact arms are directed radially towards the central circular opening. At their ends opposite the contacts, these clips project with respect to the periphery of the insulating plate and have a form allowing their connection by soldering with an electrical circuit (hole or hook).

Substantially in the place of each insulating plate playing the role of stator, insulating parts (generally of the same thickness) are stacked on the shaft and can be rotated by the latter by means of its flats. On these insulating parts, which play the role of rotor, are fixed in planes perpendicular to the shaft, one or more flat metallic parts, annular and cut out to suitable shapes, mostly called circuits, placed exactly at the clamping level of the contact clips borne by the insulating parts playing the role of stator. The appropriate cut-outs consist of radial slots along a certain angle and such that when one of these slots is opposite one of the clips, the two jaws of the latter are simply contacting each other: there is therefore no electrical connection with the metallic part or circuit of the rotor. On the other hand, when a non-slotted portion or finger of the metallic part of the circuit comes, in consequence of the rotation of the shaft, opposite a contact clip, it slides between the two jaws of the clip, whose edges are raised with the object of facilitating this introduction, and establishes an electrical connection between the rotor circuit and the contact clip. The slots, whose width is not limited, can occur over almost the entire periphery of the rotor circuit and leave only a finger which enters successively into contact with all the clips of the stator when the shaft is rotated.

The stator carries in addition a contact clip having arms longer than that of the other clips and of which the contact zone, closer to the centre of the rotor than that of ice the other clips, is thus placed beyond the bottom of the slots. This clip is thus always in electrical contact with the rotor, whatever the position of the latter; it is called feed clip or long clip. At each position of the rotor there thus corresponds one or several short clips placed in electrical contact with the long clip by means of the rotor.

The switch comprises furthermore a detent system (generally ball-type) such that the stationary positions of the rotor correspond exactly to the position of the contact clips borne by the stator. The assembly of a stator and of a rotor, commonly called a wafer, constitutes one stage of the switch.

The insulating plates playing the role of stators can comprise contact clips on their two faces: in this case, insulating plates of the rotors carry also a circuit on each of their faces. The circuits of such a wafer can be electrically isolated or connected between themselves.

On the same face of a rotor, the circuit can itself be divided into several circuits, electrically insulated from one another and each occupying a part of the total circumference. There can be obtained from one type of wafer, by varying the circuits, the slots and the contacts, an almost unlimited number of types of electric connections.

In the realisation of such known devices, the majority of the contact clips is fixed directly to insulating plates which play the role of stators, by rivets (solid or hollow). The riveting operation, however careful it may be, always damages the contact clip exactly at its point of anchorage. As a result of this, on the one hand, the value of the pressure of contact of the clip initially contemplated is modified to an absolutely unknown extent and, on the other hand, a too brutal rivetting weakens the clip exactly at its point of anchorage, and it is noticed that after a certain number of operations (which number can be of the order of several tens to several hundreds of thousands), a large proportion of the clips break, exactly at the point which had sustained a weakening at the time of rivetting. Furthermore, the fixing rivets having generally a circular head, the two blades of the contact clip work as a restrained beam at one end (in the sense of material resistance) under particularly unfavorable conditions, inasmuch as the point of anchorage is at a different distance from the pressure point for each of the considered longitudinal elements of the beam.

In addition, the presence of metallic rivets which traverse the clips located opposite faces of the stator requires, in order to insulate the said clips, recourse to special clips with large perforations, and to insulating intermediate parts, expensive and of complex manufacture.

On the other hand, in these devices with known wafers, at the time of the soldering of electrical connection to the tails of the contact clips, splashes of fluxes, especially of resins, contained in the solders as well as combustion fumes, are liable to be deposited upon the contact zones of the clips. The electric contact between the latter and the metallic or circuit" parts of the rotor can only, in consequence, be assured at the price of delicate and inconvenient precautions, or by the aid of difficult cleaning operations which risk changing the shape of the contact clips. Furthermore, the fact that at the time of use of these known devices, the surrounding air which circulates around the contact zones of the clips deposits dust on the latter and the fact that the circulation of corrosive gases alters the state of the surface of the said contact zones, does not allow the assurance of an electrical contact of good quality.

The invention has for an object a switch wafer of the type described above, having exactly the same possibilities (including dimensional) but palliating the principal faults which known switch wafers possess.

.An electric switch wafer according to the invention, comprising a substantially annular stator of an insulating material upon which are mounted electrical contact clips, 3. central rotor of an insulating material carrying metallic or circuit parts, to establish electric connections with the said clips and adapted to be rotated by a driving shaft, is characterised in that the positioning of the contact clips on the body of the stator is effected by the cooperation of projections and of recesses.

The invention will be well understood from the description which follows, given by way of example, with reference to the accompanying drawing, in which:

FIGURE 1 is a plan view of a stator of an electric switch wafer according to the invention;

FIGURE 2 is a cross-sectional View along the line 2--2 of the FIGURE 1;

FIGURE 3 is a plan view of a disc of a wafer according to the invention;

FIGURE 4 is a cross-sectional view along the line 44 of the FIGURE 3;

FIGURE 5 is a plan view of a block of a rotor circuit;

FIGURE 6 is a plan view of a half rotor of a wafer according to the invention;

FIGURE 7 is a cross-sectional view along the line 7-7 of the FIGURE 6;

FIGURE 8 is a plan view of a wafer according to the invention;

FIGURE 9 is a cross-sectional view along the line 9-9 of the FIGURE 8;

FIGURE 10 is a plan view of a half contact clip of a wafer according to the invention, on a larger scale;

FIGURE 11 is a cross-sectional view along the line 1111 of FIGURE 10;

FIGURE 12 is a partial view, on a slightly enlarged scale, illustrating the mounting of a contact clip.

(1 Stator The wafer according to the invention is composed of a stator comprising a body 1 in the shape of a ring made by moulding plastics material, preferably thermo-setting. The contact clips 2 are not fixed on this body, contrary to the stators of wafers of conventional switches, but simply applied, in suitable radial positions, on these two faces 19 and 20. The maintenance in direction and in position of the contact clips 2, which, according to a feature of the invention, are constituted by two half clips, is assured, on the one hand, by grooves 11 directed radially, limited lateral radial faces 12 and 13 and a bottom 14, obtained by moulding in the body of the stator, and whose width is only very slightly greater than that of the clips. The latter are anchored thus in these grooves with very little play. On the other hand, in each of these grooves is provided a lengthened boss 15, also formed by moulding, directed radially with lateral faces 16 and 17 and an external face 18, and which penetrates without play into an opening of conjugate shape formed in the body of each contact half-clip. The above arrangements thus ensure a strict positioning of the contact clips, both transversely and longitudinally. Final immobilisation of the contact clips in the direction perpendicular to the plane of the body 1 of the stator is obtained by the application, upon the two faces 19 and 20 of the said body, of discs 21 and 22 (FIGURES 3 and 4) of plastics material, rigidly fixed to the body 1 by means of rivets 23 (FIGURE 9) passing through holes 24 of the two discs and passing through corresponding holes 25 formed in the body 1 between the grooves housing the contact clips.

The discs 21 and 22 have, on their face 26 applied against the body 1 of the stator, grooves 27 in which are engaged the ends of the bosses 15 which pass through the contact clips and project with respect to the latter. Towards the centre of the discs, the constitutive wall of the latter is reduced in thickness substantially according to a ring, as shown at 28, in such a way as to allow the part of the contact clips overhanging on the body 1 of the stator the freedom of flexion which is necessary for the passage between their arms of the flat metallic pieces of circuit pieces of the rotor.

On the outer circular periphery of the discs 21 and 22 is formed a chamfer 29 to facilitate the bending if necessary (out of the plane of the disc) of the connector tails 30 of the contact clips, such a bending being often rendered necessary for the convenience of soldering and wiring operations.

Each of the discs 21 and 22 comprises a central circular hole of which the edge serves as a bearing for the rotor 3 of the wafer and is advantageously formed of transparent or translucent plastics material, so that the position of the rotor circuits with respect to the contact clips is visible. It can comprise on its outer face indications such as, for example, numerations of contact positions, etc.

On the discs and the body of the stator are provided two diametrically opposite openings, 31 and 32 for the body, and 33, 34 respectively, for the discs, with standard separation, intended for the passage of pillars for connecting wafers with each other, and/or for connecting the Wafer with the actuating system.

In the switch wafer device according to the invention, the contact clips simply immobilised flat between the body of the stator and a disc, as soon as the latter are rigidly fixed, are in no way damaged by their fixing and the anchoring line of the flexible arms can be almost a straight line.

No metallic connecting element crosses the contact clips, the said clips situated on the two faces of the stator are from their positioning, electrically isolated from one another.

Furthermore, the contact clips are protected and shielded by the discs, in such a way that, during manipulations of mounting or of use, the said clips, which are frangible, are protected from an .accidental shock or deformation. Furthermore the discs form a sort of protective casing which shelters the contact clips from the deposition of dust and which, in reducing to an extremely low value the air circulation, effectively protects the contact zones of the clips from changes due to possible corrosion.

(2) Rotor In the switch wafer device according to the invention, the rotor 3 (FIGURES 6 and 7) is constituted by two identical parts or halves 40, advantageously obtained by moulding from an insulating material. Each of the said rotor halves carries one or more circuits 41 intended to ensure electrical communication with the contact clips.

For the manufacture of one of the halves of the rotor, there is used a small flat plate which is circular or a disc 50, having a central perforation 51 (FIGURE 5), circular, and holes 52 angularly spaced, separated by radial slots 53 which open into the circular opening 51. The small plate is placed in a mould and by moulding of insulating plastic material thereon, the body 54 of the rotor half is firmly attached to the metallic disc 50, the filling by plastics material of the holes 52 and the slots 53 ensuring a good mutual anchorage of the body of the demi-rotor and of the disc. In the course of the operation of over moulding, upon one of the faces of the planar metallic disc, a small collar 55 of insulating material is forrned, which has pins 57 and sockets 58 of a diameter and of a depth corresponding to that of the pins, the sockets and pins being alternated and regularly spaced angularly. On the face of the metallic disc 50 opposed to that upon which is formed the small collar 55, is arranged, in the course of the over moulding, a first collar, of slight height, 59, which bounds with a small collar of circular outer contour 60, a step 61. The outer diameter of the small collar is such that each half-rotor 40 can pivot in the central opening of the associated disc 21 which serves as a bearing for it, the collar of slight height 59 resting in the course of the rotation upon the edge 35 of the central opening of the disc.

The body of each of the half-rotors 40 has a central opening 62 of which the shape is conjugated with that of the drive shafts, that is to say has two diametrically opposite flats 63 and 64 connected by circular portions.

The pins 57 and the sockets 58 are arranged in such a way that, when assembling the two half-rotors, the pins of one of the small collars 55 are introduced into the sockets of the other, the central openings 62 of each of the half-rotors are exactly superposed, the flats of the opening of one of the half-rotors prolonging the flats of the opening of the other.

Before mutual assembly of the half-rotors by the pins and the sockets of their small collar, there are formed on each of the metallic discs 50 the desired peripheral cut-outs 65, intended to give to the said discs their definitive role of switching circuits, or not switching circuits, on the passage of the stator contacts 30.

Certain of the slots 53, which are radial, are intended to allow, after over-moulding, a possible sectioning (by cutting) of the circuit block, by dividing into a series of juxtaposed sectors, providing as many separate circuits as may be required (in principle six at the maximum: in the case of wafers with six circuits-two positions). Cutting lines 53' have been shown in discontinuous line in FIGURE 5.

The formation of peripheral cut-outs 65 can naturally be effected in the course of the same operation as that of the possible cutting out of sections of the metallic discs 50 into separate circuits along the cutting lines 53'. This operation, which consists solely in recessing in a flat metal sheet, only necessitates extremely simple toolings and little difiiculty, contrary to the manufacturing methods of previously known devices where circuits are fixed by folded staples and by rivetting on the rotor.

In the device according to the invention, the positioning of the slots and/or cut-outs with respect to the flats 63 and 64 of the central hole 62 for the passage of the shaft results in an almost absolute angular precision during the formation of the said slots and/or cut-outs, which precision absolutely cannot be achieved in previously known devices.

The fact that the metallic part 50 or circuit block is plane (without bending nor rivetting) allows the use, for the manufacture of circuits, of extremely hard and rigid alloys, resulting especially in properties of wear resistance which cannot be contemplated in previously known devices. The rigidity of the metal of the circuits allows, on the other hand, reduction of the thickness to values appreciably lower than those of known circuits. There thus results, advantages of two types: first, economy when using, as frequent, precious metals and above all the fact that, during the passage of a circuit 41 between zones of contact 67 of the two arms of the contact clip 2, it only opens the latter to a slight extent, diminishing thus to a great extent fatigue of the contact clips, the length of life of the wafer being thereby considerably increased.

This reduction in circuit thickness leads, by a reduction of the force necessary for the opening of the contact clips to a substantial reduction in the torque resistance of the switch, this factor being more particularly important when the switches are driven by step by step motors of obviously limited power. One can thus by using switch wafers according to the invention, increase the number of wafers borne by a single shaft.

Finally, the manufacture of rotors according to the invention besides leading to a considerable economy in operations and toolings, permits a stock of moulded halfrotors to be kept, comprising their associated circuit profiles which can be slotted and/or cut-out on demand for completion and mounting.

(3) Bearings As mentioned above each half-rotor 40 has a collar 60 adapted to pivot in the central opening of an associated disc. The complete rotor thus pivots on two bearings arranged in the discs 21 and 22. Inasmuch as the half-rotors are supported by the edge 35 of the openings of the discs which serve as their respective bearings, and taking into account that the discs are themselves centred upon the body 1 of the stator due to the passages 33 and 34, to the passages 31 and 32 and to the rivets 23, a perfect concentricity and without play of the rotor-stator assembly is obtained, avoiding all interfering rubbing. The dimensional precision and precision of positioning of the rotor 3 allows, should it arise, the lubrication of the support zones forming bearings in the discs. Thus an additional reduction is obtained of the resistant torque of the switch and, in addition, an improvement in the protection of the contact clips against dust and corrosion in isolating them even better from the penetration of the surrounding atmosphere.

In other respects, the fixing of the circuits 41 elfect ed by a very slight anchoring in the core or body 54 of the half-rotors 40, allows the appreciable reduction, with respect to circuits of previously known devices, in the total diameter of the said circuits, approaching thus the shaft of the rubbing zones, distributed on a circle, of the contact clips 2 and of the 'feed clip.

This reduction in diameter enables, on one hand, an additional lowering of the resistant torque, at equal contact pressures, and on the other hand the lengthening of the arms of the contact clips, of which the short length is one of the main faults of known switch devices, this short length requiring the use of thin metals of a great fragility and leading, furthermore, to a rapid fatigue by workhardening.

(4) Contact clips In the switch wafer device according to the invention, the contact clips are constituted by two identical half-clips '66 (FIGURES 10, 11 and 12). Each of the contact halfclips have a contact zone of softened form 67 with raised edges, obtained by stamping. Beyond this contact Zone, the half-clips are absolutely flat Without any bend up to the connector tail 30. A possible first elongated perforation 68 allows augmentation of the flexibility of the working arm without necessitating the use of a thinner metal.

A second elongated perforation '69 allows the positioning of each of the contact half-clips on the radiating bosses 15 of the body 1 of the stator, ensuring simultaneously the radial positioning of each half-clip and its longitudinal fixing. A boss 15 cooperates, according to the invention, with two half-clips, located in mirror symmetry, whose union constitutes a contact clip.

A third perforation 70 arranged in the tail 30 beyond the stator is intended for connection with the electrical coupling conductors.

The half-clips 66 being flat and possessing no bend, the contact pressure is obtained by the deformation of the branches, as well shown in FIGURE 12, resulting from the clamping action of the half-clips between the disc (disc 21 on the drawing) and the body 1 of the stator which carries it. As a matter of fact, the contact zones 67 projecting with respect to the plane of each half-clip, repel each other mutually in flexion when their arms are applied one against the other by clamping action between the body of the stator and the associated disc.

This embodiment of the contact clips according to the invention is particularly advantageous in that the halfclip being flat, with the exception of their contact zone, I

the metal in which they are formed is not damaged in the course of a bending operation and thus has a much greater strength against fatigue and to cold-drawing, conferring on the wafer a length of life for equal work,

ing to the invention, cut out and formed in a metal in the soft state. This metal, alloy of silver, nickel, magnesium, is then tempered by heating in a hydrogen atmosphere at 550 C. This operation gives it high hardness and elasticity (close to those of a Phosphor bronze in spring state).

The half-clips thus possess, at the time of placing in service, a state of the tempered type absolutely free of all cold-drawing. Their length of life is thereby multiplied dozens of times.

Furthermore with such an alloy, advantageously 99% silver, the electrical conductivity is better than that realised with metals usually employed for contact clips of known switch wafers with, consequently, an extremely low ohmic contact resistance.

The contact clips according to the invention, also allow the operations of wiring or of connecting a switch wafer to the rest of the electrical circuits to be facilitated. In fact, in such operations, the end projecting out of the stator frequently has to be bent. When such an operation is effected on the contact clips of a device according to the invention, the effect is to displace slightly one with respect to the other, solely in the zone of the connector tail, the ends of the two contact half-clips whose union forms a clip properly so-called, without modifying the originally obtained and verified contact pressure.

What is claimed is:

1. An electric switch wafer assembly, comprising a substantially ring shaped stator formed of an electrical insulating material and having a centrally arranged opening therethrough, said stator having a pair of oppositely directed faces, each face of said stator having a plurality of angularly spaced radially extending grooves, a boss located within each groove in said stator, said bosses secured to and extending perpendicularly from the faces of said stator, a plurality of radially extending contact clips formed of an electrical conducting material and each mounted within one of said grooves in said stator, each of said contact clips having an opening arranged to engage said boss in said groove in closely fitting engagement, said contact clips projecting inwardly within the opening through said stator, an annular rotor formed of an electrical insulating material and mounted within the opening in said stator, said rotor having a centrally arranged opening adapted to be mounted on a rotary drive shaft for rotating said rotor within said stator, at least one substantially flat metallic element formed integrally with and extending radially outwardly from the periphery of said rotor and arranged to cooperate with said contact clips for establishing electrical connections, a disc made of electrical insulating material mounted on each of said faces of said stator with each said disc having a. plurality of angularly spaced recesses arranged to receive said bosses on said stator in closely fitting engagement for maintaining said contact clips in position, and means located on said discs and stator for interlocking said discs and stator together.

2. An electric switch wafer assembly, as set forth in claim 1, wherein said discs are formed of a translucent material.

3. An electric switch wafer assembly, as set forth in claim 1, wherein each of said discs having a central circular opening therethrough, said rotor shaped at its outer peripheral edges to form a shoulder for engaging the periphery of the central opening in each of said discs whereby the opening-in said discs rotatably guides said rotor. I

4. An electric switch wafer assembly, as set forth in claim 3, wherein said rotor is comprised of two rotor halves joined together in a plane parallel with the plane of said stator, each of said rotor halves having a joining surface arranged to engage the joining surface of the other said rotor half, angularly spaced means in said joining surfaces for interengaging' said rotor halves, and said discs being arranged to secure said rotor halves together.

5. An electric switch wafer assembly, comprising a substantially ring shaped stator formed of an electrical insulating material and having a centrally arranged opening therethrough, said stator having a pair of oppositely directed faces, each face of said stator having a plurality of angularly spaced radially extending grooves, a plurality of radially extending contact clips formed of an electrical contacting material each mounted within one of said grooves in said stator, means secured to said stator within said groove for holding said contact clips in position, each of said contact clips comprised of two separate half clips both located in the same said groove of said stator, each said half clips being formed of a fiat strip with the radially inner end thereof located within the opening through said stator being shaped to provide a partly rounded contact section, the contact sections of two cooperating said half clips located within the same said groove having their convex surfaces facing one another, an annular rotor formed of an electrical insulating material and mounted within the opening in said stator, said rotor having a centrally arranged opening therethrough adapted to be mounted on a rotary drive shaft for rotating said stator within said rotor, at least one substantially flat metallic element formed integrally with and extending radially outwardly from the periphery of said rotor and being located within the opening in said stator, said metallic element being arranged to pass between and in engagement with the contact sections of said half clips, a disc made of electrical insulating material mounted on each of said faces of said stator with said each disc arranged to be mounted in closely fitting interengagement with said stator for maintaining said half clips in position, and means located on said discs and stator for interlocking said discs and-stator together.

References Cited UNITED STATES PATENTS 2,554,724 5/1951 Williams. 2,828,393 3/1958 Wingard. 3,213,211 10/1965 Allison.

3,248,488 4/1966 Stephan. 3,254,164 5/ 1966 Lewandowski.

H. O. JONES, Primary 'Examiner US. Cl. X.R. 200-11 

